It is known to use life safety devices within a building or other structure to detect various hazardous conditions and/or provide a warning to occupants of the building of the detected hazardous condition. Examples of well known life safety devices include smoke detectors and carbon monoxide detectors. Some life safety devices include both the capability to detect a hazardous condition, for example smoke, and to generate an audible and/or visual alarm to provide an alert that a hazardous condition has been detected. Other life safety devices are configured to detect a hazardous condition, and when a hazardous condition is detected, send a signal to a remote life safety device, for example an alarm device, which generates the alarm. In each case, a hazardous condition is detected and an alarm generated warning of the hazardous condition.
In a building with multiple rooms or levels equipped with conventional life safety devices, the occupants of the building may not be adequately or timely warned of a hazardous condition that has been detected in a part of the building not presently occupied by the occupant. Attempts to remedy this problem include the use of detectors that communicate with one another via radio frequency (RF) signals in which the detector that detects a hazardous condition sends an RF signal to other detectors in the building thereby triggering a warning on those detectors (see, e.g., U.S. Pat. Nos. 5,587,705 and 5,898,369), and detectors that are hardwired interconnected to one another and/or to one or more monitoring or signaling units (see, e.g., U.S. Pat. No. 6,353,395).
The use of RF interconnected life safety devices is attractive as an existing building, for example a home, can be equipped with the safety devices without the need to run new wiring throughout the building. RF interconnected life safety devices are also beneficial because many buildings have high ceilings on which the safety devices are most suitably placed for optimum detection. This can make it difficult to physically access the safety devices, which has been previously necessary to conduct the recommended periodic testing of each safety device and to silence the safety device after it has started signaling an alarm. Examples of using RF signals to communicate between life safety devices during testing are disclosed in U.S. Pat. Nos. 4,363,031 and 5,815,066.
Despite the existence of life safety devices using RF communications, there is a need for improvements in RF communications between RF configured life safety devices.